Members of the Free Syrian Army celebrate in front of a burning tank after defeating government troops in Rasten, near Homs, May 14, 2012. Picture taken May 14, 2012.

REUTERS/Handout

UNITED NATIONS (Reuters) – Syria remains the top destination for Iranian arms shipments in violation of a U.N. Security Council ban on weapons exports by the Islamic Republic, according to a confidential draft report by a U.N. panel of experts seen by Reuters on Wednesday.

Iran, like Russia, is one of Syriaâ€™s few allies as it presses ahead with a 14-month old assault on opposition forces determined to oust Syrian President Bashar al-Assad.

The report, which the expert panel has submitted to the Security Councilâ€™s Iran sanctions committee, said there were three seizures of large shipments of Iranian weapons investigated by the panel over the past year.

â€œTwo of these cases involved the Syrian Arab Republic, as were the majority of cases inspected by the Panel during its previous mandate, underscoring that Syria continues to be the central party to illicit Iranian arms transfers,â€ it said.

â€œThe Panel recommends the designation (blacklisting) of two entities related to these interdictions,â€ it said. â€œThe report also takes note of information concerning arms shipments by Iran to other destinations.â€

The report also discusses Iranâ€™s attempts to circumvent sanctions on its nuclear program but notes that the four rounds of punitive measures the 15-nation Security Council imposed on Iran between 2006 and 2010 were having an impact.

â€œSanctions are slowing Iranâ€™s procurement of some critical items required for its prohibited nuclear program,â€ it said. â€œAt the same time prohibited activities continue, including uranium enrichment.â€ The report talks at length about Islamic Republic of Iran Shipping Lines, known as IRISL. While IRISL itself is not formally under U.N. sanctions, three of its subsidiaries have been sanctioned and the council has warned U.N. member states to be vigilant regarding potential sanctions violations by IRISL.

The panel report says that one of IRISLâ€™s sanctioned subsidiaries, Irano Hind Shipping Company, continues to operate vessels. It also says that IRISL is a challenging company to monitor as it is constantly changing the ownership, names and national flags of its ships.

Diplomats told Reuters that the panelâ€™s draft report may be changed by the Security Councilâ€™s Iran sanctions committee before it is submitted to the council itself for consideration. Last yearâ€™s expert panel report on Iran was never made public because Russia blocked its publication.